ios - 如何修复 Swift 中的 "ActionSheet of UIAlertController has the conflict constraint"错误

Question

我的代码在iOS12.1上运行成功，但是最近当我将iOS、Xcode、macOS的版本更新到iOS12.2 Xcode10.2和macOS10.14.4时，我的项目出现了问题。我的应用程序界面没有问题，但是当我打开操作表时，它告诉我我的约束有冲突。我该如何解决？ this is my UI this is the warning in Xcode

我重新设置了接口(interface)的约束，但是不管怎么弄，还是一样的问题。

这些是我的代码，一旦我点击按钮，就会出现操作表，Xcode 告诉我我的约束有冲突

@IBAction func newToDoBarButtonTapped(_ sender: UIBarButtonItem) {

        let alertController = UIAlertController(title: "New or Edit", message: nil, preferredStyle: .actionSheet)
        let newToDoAlertAction = UIAlertAction(title: "New Item", style: .default, handler: {(_) in
            let mainStoryboard = UIStoryboard(name: "Main", bundle: nil)
            let registerVC = mainStoryboard.instantiateViewController(withIdentifier: "NewToDoStoryboard") as! ToDoViewController
            self.navigationController?.pushViewController(registerVC, animated: true)
        })

        let editInformationOfListAction = UIAlertAction(title: "Edit Information", style: .default, handler: {(_) in
            let mainStoryboard = UIStoryboard(name: "Main", bundle: nil)
            let registerVC = mainStoryboard.instantiateViewController(withIdentifier: "EditStoryboard") as! EditItemTableViewController
            self.navigationController?.pushViewController(registerVC, animated: true)
        })

        let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)

        alertController.addAction(newToDoAlertAction)
        alertController.addAction(editInformationOfListAction)
        alertController.addAction(cancelAction)

        self.present(alertController,animated: true,completion: nil)
    }

我除了没有约束冲突的警告。

Answer 1

您可能必须手动关闭约束警报。

   @IBAction func newToDoBarButtonTapped(_ sender: UIBarButtonItem) {
     ...
    self.present(alertController,animated: true,completion: nil)

   alertController.view.subviews.flatMap({$0.constraints}).filter{ (one: NSLayoutConstraint)-> (Bool)  in
      return (one.constant < 0) && (one.secondItem == nil) &&  (one.firstAttribute == .width)
   }.first?.isActive = false

  }